Locating an object in an unfamiliar and dense physical environment, such as a control room, supermarket, or warehouse, can be challenging. In this paper, we present the Projection-Augmented Arm (PAA), a motorized robotic arm augmented with a pico-projector to help users to localize targets in such environments. The arm moves and displays a projected spotlight on the target. We present the results of a study that shows that the PAA helps users to more quickly locate target objects in a dense environment. We further study the influence of the visibility of the projected spotlight while moving versus that of the physical movement of the projection arm on user performance and search strategy, finding that 1) information about the orientation of the arm has a stronger impact on performance however following the moving spotlight on the walls did not significantly improve performance; 2) the orientation of the arm is especially useful when the target is behind the user (36.33 % improvement); and 3) users’ strategies relied mainly on the arm when it is visible.